Autologous stem cell transplantation in POEMS syndrome: Multicenter real-world treatment patterns and outcomes.

POEMS syndrome is a rare multisystem plasma cell disorder for which evidence guiding management is largely derived from single-center retrospective series. We conducted a retrospective multicenter study including all consecutive patients diagnosed between January 1995 and June 2024 across nine referral hospitals in Catalonia, Spain, within the GEMMAC collaborative network. Clinical characteristics, treatment strategies, transplant outcomes, and long-term survival were analyzed. Forty patients were included, with a median age of 65 years; 25 underwent autologous stem cell transplantation (ASCT). Hematologic response to first-line therapy was achieved in 77.5% of patients. After a median follow-up of 94.2 months, median progression-free survival was 102.6 months and median overall survival was 146.9 months, with 5-year rates of 69.0% and 87.6%, respectively. ASCT was associated with deep and durable hematologic and clinical responses. Baseline ECOG performance status and depth of hematologic response correlated with outcomes. VEGF levels declined markedly after treatment, particularly following ASCT. Transplant-related toxicity was manageable, although late complications were observed. These findings support ASCT as a central therapeutic strategy in eligible patients and underscore the need for long-term follow-up.